Resection devices and related methods of deployment

ABSTRACT

A medical/surgical device for performing tissue resection can include an endoscope with proximal and distal ends, defining working channels, and a snare assembly located in one of the working channels. The working channel may include a bend near the distal end and towards the outward radial wall of the endoscope. The snare assembly may include a snare loop and an actuation element imparted with the pre-formed angular bends and an actuation control handle. The bends of the actuation element and the working channel may be the same. The rotational manipulation of the actuation element may synchronize the pre-formed bend of the actuation element with the bend of the working channel to concentrically (or otherwise) align the deployed snare loop with the endoscope or endoscope attachments.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/837,795, filed Jun. 21, 2013, the disclosure of which is incorporatedherein by reference in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to resection devices andmethods for deployment and, in particular, to a rotating andself-aligning snare configured for deployment for tissue resection.

BACKGROUND

Tissue resection procedures, such as polypectomy, are typically carriedout by inserting introduction sheaths, such as endoscopes orlaparoscopes, into the body of a patient through incisions or naturalanatomical openings. Traditionally, such devices employ snares,typically designed as loops, for performing tissue resection procedures.For scenarios in which the tissue needs to be drawn out before thetissue can be ensnared, such devices may incorporate suction tube(s),employed in tandem with a snare for resection and retrieval of theresected tissue portion(s) from the patient's body.

In some implementations, snares, when deployed, expand into a circularloop, that may not be axially aligned with the operating ends of theendoscopic or laparoscopic attachments, such as suction tubes. Axialmisalignment of a deployed snare loop, when used with an endoscopicattachment, sometimes mandates re-deployment of the snare until thesnare loop axially aligns with the operating end of the endoscopicattachment, inside the patient's body cavity.

SUMMARY

Embodiments of the present disclosure relate to medical devices forperforming tissue-ensnaring procedures during a surgical or medicalprocedure, e.g., tissue resection from inside a patient's body.

In accordance with an aspect of the present disclosure, a medical deviceis disclosed for resecting tissue. The device includes an elongatemember defined by a proximal end, a distal end, one or more workingchannels extending from the proximal end to the distal end, and a lumenextending from the proximal end to the distal end, wherein the lumenbends radially outward from the elongate member, near the distal end;and a snare device comprising an actuation element and a snare loop,wherein the snare loop is positioned distal to the distal end of theelongate member and is coupled to an end of the actuation elementprotruding from the lumen; wherein the actuation element includes a bendat a distal end of the actuation element, wherein the bend in theactuation element interacts with the bend in the lumen to urge the snareloop into alignment with the distal end of the elongate member.

In accordance with another aspect of the disclosure, a snare device isdisclosed for deployment through an endoscope and for resection oftissue. The device includes an actuation element configured to beadvanced through a lumen extending through the endoscope and bendsradially outward from the endoscope near a distal end of the endoscope;and a snare loop coupled to an end of the actuation element andconfigured to protrude from the lumen and be positioned distal to adistal end of the endoscope; wherein the actuation element is bent at adistal end and the bend in the actuation element is configured tointeract with the bend in the lumen to urge the snare loop intoalignment with the distal end of the endoscope.

In accordance with another aspect of the disclosure, a method isdisclosed for resecting tissue using an elongate member and a snareassembly. The method includes advancing, into a patient orifice, anelongate member defined by a proximal end, a distal end, one or moreworking channels extending from the proximal end to the distal end, anda lumen extending from the proximal end to the distal end, wherein thelumen bends radially outward from the elongate member, near the distalend; and advancing, through the lumen, a snare device comprising anactuation element and a snare loop, wherein the snare loop is positioneddistal to the distal end of the elongate member and is coupled to an endof the actuation element protruding from the lumen; wherein theactuation element includes a bend at a distal end of the actuationelement, wherein the bend in the actuation element interacts with thebend in the lumen to urge the snare loop into alignment with the distalend of the elongate member.

Additional characteristics and advantages of the disclosure will be setforth in part in the description, which follows, and in part will beapparent from the description, or may be learned by practice of thedisclosure.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the disclosure, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate exemplary embodiments of thepresent disclosure and together with the description, serve to explainprinciples of the disclosure.

FIG. 1 is a schematic view of a distal portion of a resection device,with an associated snare loop depicted in an expanded configuration,according to certain embodiments of the present disclosure.

FIG. 2 is a schematic view of an exemplary snare assembly with a snareloop depicted in an expanded configuration, according to certainembodiments of the present disclosure.

FIG. 3 is a perspective view of an exemplary resection device,incorporating the exemplary snare assembly of FIG. 2, according tocertain embodiments of the present disclosure.

FIG. 4 is a cross-sectional side view of the exemplary resection deviceof FIG. 3, according to certain embodiments of the present disclosure.

DESCRIPTION OF EMBODIMENTS

Reference is now made in detail to embodiments of the presentdisclosure, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts. The term“distal” refers to the end farthest away from a user when introducing adevice into a patient. The term “proximal” refers to the end closest tothe user when placing the device into the patient.

Overview

Embodiments of the present disclosure relate to medical or surgicaldevices used to retrieve and/or sever unwanted or target tissue as wellas other unwanted or target material, such as stones, within a patient'sbody. For example, embodiments of the disclosed device may facilitateremoval of unwanted tissue, such as cancerous polyps or lesions, fromwithin a patient's body, including tissue disposed in a patient's body,e.g., on the mucosal walls of the colon, esophagus, stomach, orduodenum. A physician may also desire to resect tissue in order toconduct a biopsy or other examination. For convenience, the medical andsurgical devices discussed here can be referred to as “resectiondevices,” it being understood that such devices are equally useful forsevering or removing unwanted or target tissue.

In some embodiments, a resection device may include an endoscope,endoscopic attachments (e.g., a suction ring cap), and a snare assembly.The endoscope may include a proximal end, a distal end, and a lumenextended therebetween. The lumen may include multiple working channels.The endoscopic attachments (e.g., the suction ring cap) may be insertedthrough one of multiple working channels, to be mounted on the distalend of the endoscope and define one or more working channels of theendoscope as a suction channel. The endoscope may incorporate anotherlumen of having a cylindrical cross-section and being proximal to theradial periphery of the endoscope. The cylindrical cross-sectional lumenmay be substantially parallel to the radially outer surface of theendoscope, until the lumen curves radially outward at a distal end. Thecurvature imparted to the lumen may be toward the radially outer surfaceof the endoscope, extending the lumen through a slot provided on theradially outer peripheral surface of the endoscope, near the distal endof the endoscope.

The snare assembly may include a snare loop, an actuation element, andan actuation handle. The snare assembly may be introduced at theproximal end of the endoscope and advanced through the cylindrical crosssectional lumen. The actuation element and the snare loop may, in acollapsed configuration, propagate along the length of the curved lumenand emerge near the distal portion of the endoscope through a slot,protruding radially outward.

The actuation element of the snare may also have a pre-formed curvaturehaving an angular bend similar to the curve of the cylindrical crosssectional lumen. The actuation member of the snare assembly may coupleto the actuation handle at the proximal end and to the snare loop at thedistal end of the endoscope. The snare loop, when deployed at the distalend of the endoscope, may expand to substantial circular shape. In oneembodiment, the actuation element may be configured to rotate freely ascompelled by forces generated between the curved portion of the lumenand the curved portion of the actuation element. In another embodiment,the actuation handle at the proximal end of the endoscope may be used torotationally manipulate the actuation element, and seat the pre-formedcurvature in the actuation element on the curve in the cylindricalcross-sectional lumen, near the distal portion of the endoscope, toalign the expanded snare loop and the suction ring cap in substantiallyconcentric arrangement. The pre-formed curvature of the lumen and therotational manipulation of the actuation element may allow the deployedsnare loop to be offset from the distal opening surface of the suctionring cap, but concentrically aligned with the suction ring cap. Therotation of the actuation element may be controlled by an actuatinghandle, such as, for example, a guidewire, a resilient mechanism like aspring, or any other suitable mechanism. In various embodiments, theactuation handle may be cylindrical, rectangular, oval, elliptical,conical, and similar configurations.

In various embodiments of the disclosure, the operation of the resectiondevice may be such that the portion of the tissue drawn by the suctionchannel toward the suction ring cap may be captured, by collapsing theconcentrically aligned snare loop around the desired tissue portion, soit may then be resected by the snare. Those skilled in the art willappreciate that the endoscope and the snare assembly may includeadditional mechanisms and/or other inflatable structures, withoutdeparting from the scope of the present disclosure.

Exemplary Embodiments

FIG. 1 is a schematic diagram of an exemplary resection device 100. Theresection device 100 may be configured to be introduced into a patient'sbody through an incision or a suitable natural opening. In addition, theresection device 100 may be configured to be advanced to a desiredlocation within a patient's body with the aid of a suitable introductionsheath, such as an endoscope 102 having a distal end 104, a proximal end(not shown), and one or more working channels 106, 108 extendingtherebetween.

An operator may introduce one or more medical/surgical devices throughone or more working channels 106, 108 of endoscope 102 to extend out ofthe distal end 104 of the endoscope 102. The operator may also mount anattachment on the distal end 104 of the endoscope 102. For example,during a resectomy procedure, an operator may attach a suction ring cap110 to the distal end 104 of the endoscope 102, thus rendering one ormore channels 106, 108 as a suction channel. Another medical or surgicaldevice, such as a snare assembly 112 may be introduced, for example,into another lumen/channel (not shown). Additionally, from time to timeduring the procedure, the operator may insert a light source, a camera,an injector, or a morcellator within the one or more channels 106, 108.The proximal end (not shown) of the endoscope 102 may be connected to ahub assembly or handle (not shown) for operating the endoscope 102 andthe various devices and attachments inserted into or mounted onendoscope 102, collectively or individually.

The snare assembly 112 may further include a lumen 116, an actuationelement 114, an actuation handle (not shown), and a snare loop 118. Theactuation element 114 may extend through the entire length of the lumen116, disposed within a working channel (not shown) of the endoscope 102,and may be manipulated through the actuation handle (not shown), at theproximal end (not shown) of the endoscope 102. Manipulation of theactuation element 114 through the actuation handle may deploy the snareloop 118 at the distal end 104 of the endoscope 102.

The deployed snare loop 118 may expand into a particular shape, such asa substantial circular shape that, in some cases, may not be concentricwith the suction ring cap 110. For example, FIG. 1 depicts the snareloop 118 as being out of concentric alignment with the suction ring cap110, or the distal end 104 of endoscope 102. The axial misalignment ofthe snare loop 118 may cause various disadvantages, such as in notallowing snare loop 118 to circumferentially grip around targetedtissue, drawn towards the suction ring cap 110 by the suction channel106, 108. Accordingly, a preformed actuation element or feature(described in more detail below) may be incorporated into the snareassembly 112 and/or endoscope 102 to cause the snare loop 118 to alignwith the operating end of the endoscope 102 during operations, therebyenabling expanded snare loop 118 to effectively ensnare target tissue,drawn toward the suction ring cap 110.

FIG. 2 depicts an exemplary snare assembly 212 of a resection device(not shown), in an expanded snare loop configuration, according toprinciples of the present disclosure. The snare assembly 212 may includean actuation element 214, a snare loop 218, an interface 220 of theactuation element 214 with the snare loop 218, and an actuation handle(not shown). In various embodiments, the actuation element 214 mayinclude, without limitation, a guidewire, a spring mechanism, anactuation tube, a bracket, or a plate with one or more holes and othersimilar structure(s). The interface 220 may act as a coupling betweenthe actuation element 214 and the snare loop 218. In one example, apush-pull mechanism, such as an actuation wire, may be employed as theactuation element 214 for either manually or automatically expandingand/or retracting the snare loop 218. The manipulation(s) of theactuation element 214 may change the area captured by the snare loop 218without displacing the snare loop 218 with respect to the targetedtissue.

According to certain aspects of the present disclosure, the actuationelement 214 may be angularly curved or imparted with a predeterminedobtuse angle, with respect to a longitudinal axis of the actuationelement 214, to give it a pre-formed curvature 222. The exact locationof the pre-formed curvature 222, along the length of the actuationelement 214, may depend upon the structure of a lumen (not shown),through which the actuation element 214 may be inserted in the endoscope(not shown). The actuation element 214 may be fabricated out of anyshape memory alloy that can alter the shape of the actuation element 214through temperature variations or equivalent controlling factors, toimpart the pre-formed curvature 222 at the desired location of theactuation element 214. In one embodiment, the pre-formed curvature 222may be defined by a radius that controls how gently or sharply theactuation element 214 curves. In one embodiment, the pre-formedcurvature 222 may be defined by a relatively short radius that causes arelatively sharp or hard angle in the actuation element 214. In anotherembodiment, the pre-formed curvature 222 may be defined by a relativelylong radius that causes a relatively gentle or sloping curve in theactuation element 214.

In one embodiment, the snare loop 218 may be a wire configured to severor retrieve unwanted tissue. Further, the snare loop 218 may beconfigured in a variety of shapes, such as a continuous loop, multipleloops, a basket, polygonal loops, non-symmetrical loops, and the like.In one implementation, the snare loop 218 may be substantially circularin shape, however, other configurations may include ellipsoids. Inanother embodiment, the snare loop 218 may be configured forelectrocauterization procedures to resect tissue. For example, the snareloop 218 may be configured to conduct sufficient electric current togenerate an amount of heat desired for electrocautery. The snare loop218 may be substantially hollow with holes disposed on a surface (e.g.,an internal surface) to provide irrigation or lubrication duringelectrocauterization or any other medical or surgical procedure.Furthermore, the snare loop 218 may be configured to withstand repeatedheat cycling without developing “hot spots” and breaking down. Further,the general characteristics of suitable materials and configurations ofthe snare loop 218 known in the art may be used to select adequatematerials and configurations for snare loop 218.

In one embodiment, the snare loop 218 may be made of a suitablebiocompatible material, e.g., stainless steel or NITINOL. The snare loop218 may be coated with an antimicrobial covering to inhibit anymicrobial growth on its surface. For instance, the coating may includean anti-bacterial covering, which may contain an inorganic antibioticagent, disposed in a polymeric matrix that adheres the antibiotic agentonto the surface of the snare loop 218. Furthermore, a drug-releasingcoating may be applied to the surface of the snare loop 218 forassisting in delivery of drugs to the targeted tissue during operation.The wire of which the snare loop 218 is formed may be sufficientlyflexible to retract the snare loop 218 into the collapsed position.

FIG. 3 shows a resection device, according to an embodiment of thepresent disclosure. The resection device may be configured to beintroduced into a patient's body through an incision or a suitablenatural opening. In addition, the resection device may be configured tobe advanced to a desired location within a patient's body with the aidof a suitable introduction sheath, such as an endoscope 202 having adistal end 204, a proximal end (not shown), and one or more workingchannels 206, 208 extending therebetween. In one embodiment, theresection device may include an endoscope 202 and a snare assembly 212(as shown in FIG. 2). FIG. 3 depicts snare assembly 212 as beingconcentrically aligned with distal end 204 of endoscope 202.

Endoscope 202 may include one or more working channels 206, 208 throughwhich an operator may either introduce one or more medical or surgicaldevices to extend out of the distal end 204 of the endoscope 202. Incertain embodiments, an operator may also use an attachment to bemounted on the distal end 204 of the endoscope 202. For example, duringa resectomy procedure, an operator may attach a suction ring cap 210 tothe distal end 204 of the endoscope 202, thus rendering one or more ofchannels 206, 208 as a suction channel. Another medical or surgicaldevice, such as a snare assembly 212, may be introduced, for example,into another lumen/channel (not shown). Additionally, from time to timeduring the procedure, the operator may insert a light source, a camera,an injector, a morcellator, or other device, within the one or morechannels. The proximal end (not shown) of the endoscope 202 may beconnected to a hub assembly or handle (not shown) for operating theendoscope 202 as well as the various inserted devices and attachmentscollectively or individually.

In some of the embodiments, one or more of the lumen(s) (not shown) maybe disposed in the endoscope 202, proximal to the radially outerperiphery of the endoscope 202. The lumen may be of cylindricalcross-section and substantially parallel to the radially outer surface228 of the endoscope 202, until the lumen is curved radially outward ata distal end of the endoscope 202. The curvature imparted to the lumenmay be toward the radially outer surface 228 of the endoscope 202,extending along the lumen to a slot provided (not shown) on the radiallyouter surface 228 of the endoscope 202, near the distal end 204 of theendoscope 202.

The snare assembly 212 may further include a lumen 216, an actuationelement 214, an actuation handle (not shown), and a snare loop 218. Inone embodiment, the lumen 216 may be fixedly attached to the endoscope202 and provided with a permanent curvature at its distal end.Alternatively, the lumen 216 may be introduced from the proximal end(not shown) of the endoscope 202, into the cylindrical cross-sectionallumen (not shown). The lumen 216 may extend along the length of thelumen, substantially parallel and proximal to the radially outer surface228 of the endoscope 202 until curving radially outward near the distalend 204 of the endoscope 202. The lumen 216 may be a flexible tube thatacquires a straight profile when being inserted through endoscope 202,but acquires a curved shape at its distal end, when fully inserted andadvanced through endoscope 202. The lumen 216 may emerge from a slot ororifice (not shown) provided at the radially outer surface 228 of theendoscope 202 near the distal end 204 of the endoscope 202. The lumen216 may be fabricated from silicone, polyurethane, PVC, and/or othersuch flexible biocompatible polymers and materials.

In some embodiments, the actuation element 214 may be advanced throughthe entire length of the lumen 216 and can be manipulated through theactuation handle (not shown), at the proximal end (not shown) of theendoscope 202. Manipulation of the actuation element 214 through theactuation handle may deploy the snare loop 218 at the distal end 204 ofthe endoscope 202. In some embodiments, the actuation element 214 may beimparted with a pre-formed curvature, equivalent to the angle of thecurve of the lumen 216. In certain embodiments, the location of thecurve along the length of the actuation element 214 may be precisely thesame as the curvature of the lumen 216. In one embodiment, the actuationelement 214 may be fabricated of shape memory alloy, such as NITINOL,that, by virtue temperature-dependent properties, may allow theactuation element 214 to be imparted with the pre-formed curvature.Thus, actuation element 214 may adopt its pre-formed curvature afterbeing after introduced through the curved lumen 216, along with thecollapsed state snare loop 218 and the interface 220. In certainembodiments, the actuation element 214 may acquire its predeterminedangular shape or curvature at a location along its length such that thecurved portion is aligned with the curved portion of the lumen 216 whenthe actuation element 214 is fully deployed in the endoscope 202. In oneembodiment, the actuation element 214, along with the collapsed statesnare loop 218 and interface 220, may be introduced through the proximalend of the endoscope 202 into the curved lumen 216 using any push-pullor similar actuation mechanism, which may be manipulated from theactuation handle (not shown) at the proximal end of the endoscope 202.

FIG. 4 depicts a cross-sectional side view of a schematic of anexemplary resection device, according to an embodiment of the presentdisclosure. The resection device may include an endoscope 202, having aproximal end (not shown), a distal end 204, and a lumen 226 extendingtherebetween. The lumen 226 may further include multiple workingchannels (206, 208, as shown in FIG. 3), which an operator may use tointroduce one or more medical or surgical devices or attachments to bemounted or used at the distal end 204 of the endoscope 202. Themedical/surgical devices or attachments may be introduced from theproximal end (not shown) of the endoscope 202, to extend out of thedistal end 204 of the endoscope 202.

In some embodiments, apart from the working channels (206, 208, as shownin FIG. 3) available in the lumen 226, additional lumen(s) 224 may bedisposed in proximity to the radially outer surface 228 of the endoscope202. One such lumen 224 of cylindrical cross-section may be disposed inthe endoscope 202, between the proximal end (not shown) and slot 230,provided on the radially outer surface 228. Lumen 224 may terminate ator around its distal end at a slot 228 provided on the radially outersurface 228 of the endoscope 202. As described above, lumen 216 mayextend through lumen 224 and be imparted with an angular curve at apredetermined location, along its length, proximal to the distal end 204of the endoscope 202. The imparted curve may be at an obtuse angle withthe longitudinal axis of the endoscope 202. The angle and the preciselocation at which the curvature is introduced in the lumen 216 maydepend upon factors, such as, the location of slot 228, and a desiredposition of snare loop 218.

As described above, during a resectomy procedure, an operator mayintroduce a snare assembly 212 through the lumen 224, from the proximalend (not shown) of the endoscope 202. The snare assembly 212 may includelumen 216, an actuation element 214, a snare loop 218, an intersection220 between the actuation element 214 and the snare loop 218, and anactuation handle (not shown). The lumen 216 and the actuation element214 may each be angularly curved, at locations along their lengths suchthat they align when the actuation element 214 and its snare loop 218are fully deployed.

As described above, the curvature 222 may be imparted into actuationelement 214 before the snare assembly 212 is introduced in the lumen224. The actuation handle (not shown) at the proximal end (not shown) ofthe endoscope 202 can be manipulated to advance the snare assembly 212along the cylindrical lumen 224. As the actuation element 214, with thepre-formed curvature 222, reaches the curve of the lumen 116,longitudinal force may be applied to the actuation element 214 and orthe lumen 216 to cause the snare loop 218 to emerge from the lumen 224,through the slot 230, provisioned on the radially outer surface 228.Moreover, as actuation element 214, with the pre-formed curvature 222,reaches the curve of the lumen 116, respective forces between theactuation element 214 and lumen 116, by virtue of their respectivecurved portions, may cause actuation element 214 to rotate to a desiredorientation that aligns snare loop 218 concentrically with the distalend 204 of endoscope 202.

Specifically, the rotational movement of the actuation element 214 mayalign the expanded snare loop 218, e.g., concentrically, with an openingin the suction ring cap 210 or generally with a distal end of endoscope202. In one embodiment, an actuation handle may be used to rotationallymanipulate the actuation element 214 for concentric alignment of thesnare loop 218, and may be included in the actuation hub (not shown)used for overall deployment of the resection device 200 or individualcontrols. In another embodiment, the pre-formed curvature 222 ofactuation element 214 may act in conjunction with the curve of the lumen216 to automatically cause the snare loop 218 to become concentric (orotherwise aligned) with the lumen 226 and the distal end 204 of theendoscope 202. In some embodiments, the deployed snare loop 218 may belongitudinally offset from the opening surface of the suction ring cap210 to provide a better circumferential grip around the targeted tissue.

It should be apparent that the resection device 200 is useful to performsurgical, diagnostic, and therapeutic procedures in a wide variety ofbodily locations. For example, removal of polyps detected during aroutine colonoscopy could quickly be accomplished using the methoddiscussed above. Additionally, stones or unwanted deposits can beengaged and removed from a variety of body lumens such as ureters,bladders, or the urethra. These and other procedures can be accomplishedwithin the scope of the present disclosure.

Embodiments of the present disclosure may be used in various medical,surgical, or non-medical procedure, including any medical procedurewhere appropriate resection of undesired or target body tissue isdesired. In addition, at least certain aspects of the aforementionedembodiments may be combined with other aspects of the embodiments, orremoved, without departing from the scope of the disclosure.

Other embodiments of the present disclosure will be apparent to thoseskilled in the art from consideration of the specification and practiceof the embodiments disclosed herein. It is intended that thespecification and examples be considered as exemplary only, with a truescope and spirit of the disclosure being indicated by the followingclaims.

What is claimed is:
 1. A medical device for resecting tissue, the devicecomprising: an elongate member defined by a proximal end, a distal end,one or more working channels extending from the proximal end to thedistal end, and a lumen extending along an inside of a radially outersurface of the elongate member from the proximal end to the distal end,wherein the lumen bends radially outward from the elongate memberthrough a slot in the outer surface near the distal end of the elongatemember; and a snare device comprising an actuation element and a snareloop, wherein the snare loop is positioned distal to the distal end ofthe elongate member and is coupled to a distal end of the actuationelement protruding from the lumen; wherein the lumen bends radiallyoutward near the distal end of the actuation element; and wherein theactuation element includes a bend at a distal end of the actuationelement, wherein the bend in the actuation element interacts with thebend in the lumen to urge the snare loop into alignment with the distalend of the elongate member.
 2. The medical device of claim 1, whereinthe lumen extends along a longitudinal axis radially outward from acentral axis of the elongate member and bends radially away from thecentral axis of the elongate member near the distal end of the actuationelement.
 3. The medical device of claim 1, wherein the actuation elementis configured to rotate freely such that relative forces between thebend in the actuation element and the bend in the lumen can cause theactuation element to rotate.
 4. The medical device of claim 1, whereinthe bends of the actuation element and the lumen are both curvedaccording to a common radius of curvature or bent at a common angle. 5.The medical device of claim 1, wherein the actuation element is curvedat a location along its length selected to cause the snare loop to belongitudinally offset from the distal end of the elongate member by apredetermined amount when the bend in the actuation element is alignedwith the bend in the lumen.
 6. The medical device of claim 1, whereinthe distal end of the elongate member contains a suction cap and thesnare loop is configured to be concentrically aligned with the suctioncap when the bend in the actuation element is aligned with the bend inthe lumen.
 7. The medical device of claim 1, wherein the actuationelement and the snare loop are formed from a shape memory alloymaterial.
 8. The medical device of claim 1, wherein the actuationelement and the snare loop are configured to be collapsed into arelatively straight configuration when being advanced or retractedthrough a straight portion of the lumen.
 9. The medical device of claim1, wherein the actuation element is configured to be advanced throughthe lumen until a predetermined position at which the actuation elementrotates to self-align the snare loop and return to an original curvaturematching the bend in the lumen.
 10. The medical device of claim 1,wherein the lumen includes a tubular portion fixedly attached to theendoscope.
 11. The medical device of claim 1, wherein the lumen includesa flexible tubular portion configured to be advanced through theelongate member to a region near the distal end of the elongate member.12. A snare device for deployment through an endoscope and for resectionof tissue, the device comprising: an endoscope; an actuation elementconfigured to be advanced through a lumen extending along an inside of aradially outer surface of the endoscope, wherein the lumen bendsradially outward through a slot in the outer surface of the endoscopenear a distal end of the endoscope; and a snare loop coupled to an endof the actuation element and configured to protrude from the lumen andbe positioned distal to a distal end of the endoscope; wherein theactuation element is bent at a distal end and the bend in the actuationelement is configured to interact with the bend in the lumen to urge thesnare loop into alignment with the distal end of the endoscope.
 13. Thesnare device of claim 12, wherein the actuation element is configured tobe advanced through the lumen, wherein the lumen extends along alongitudinal axis radially outward from a central axis of the endoscopeand bends radially away from the central axis of the endoscope.
 14. Thesnare device of claim 12, wherein the actuation element is configured torotate freely such that relative forces between the bend in theactuation element and the bend in the lumen can cause the actuationelement to rotate.
 15. The snare device of claim 12, wherein the bendsof the actuation element and the lumen are both curved according to acommon radius of curvature or bent at a common angle.
 16. The snaredevice of claim 12, wherein the actuation element is curved at alocation along its length selected to cause the snare loop to belongitudinally offset from the distal end of the elongate member by apredetermined amount when the bend in the actuation element is alignedwith the bend in the lumen.
 17. The snare device of claim 12, whereinthe actuation element and the snare loop are formed from a shape memoryalloy material.
 18. The snare device of claim 12, wherein the actuationelement and the snare loop are configured to be collapsed into arelatively straight configuration when being advanced or retractedthrough a straight portion of the lumen.
 19. The snare device of claim12, wherein the actuation element is configured to be advanced throughthe lumen until a predetermined position at which the actuation elementis rotatable to rotate to self-align the snare loop and return to anoriginal bending state matching the bend in the lumen.
 20. A method forresecting tissue using an elongate member and a snare assembly, themethod comprising: advancing, into a patient orifice, an elongate memberdefined by a proximal end, a distal end, one or more working channelsextending from the proximal end to the distal end, and a lumen extendingalong an inside of a radially outer surface of the elongate member fromthe proximal end to the distal end, wherein the lumen bends radiallyoutward from the elongate member through a slot in the outer surfacenear the distal end of the elongate member; and advancing, through thelumen, a snare device comprising an actuation element and a snare loop,wherein the lumen bends radially outward near a distal end of theactuation element when the actuation element is advanced through thelumen, wherein the snare loop is positioned distal to the distal end ofthe elongate member and is coupled to the distal end of the actuationelement protruding from the lumen; wherein the actuation elementincludes a bend at a distal end of the actuation element, wherein thebend in the actuation element interacts with the bend in the lumen tourge the snare loop into alignment with the distal end of the elongatemember.